Adapting reinforcement learning for multimedia transmission on SDN

[EN] Multimedia transmissions require a high quantity of resources to ensure their quality. In the last years, some technologies that provide a better resource management have appeared. Software defined networks (SDNs) are presented as a solution to improve this management. Furthermore, combining SDN with artificial intelligence (AI) techniques, networks are able to provide a higher performance using the same resources. In this paper, a redefinition of reinforcement learning is proposed. This model is focused on multimedia transmission in a SDN environment. Moreover, the architecture needed and the algorithm of the reinforcement learning are described. Using the Openflow protocol, several sample actions are defined in the system. Results show that using the system users perceive an increase in the image quality three times better. Moreover, the loss rate is reduced more than half the value of losses recorded when the algorithm is not applied. Regarding bandwidth, the maximum throughput increases from 987.16 kbps to 24.73 Mbps while the average bandwidth improves from 412.42 kbps to 7.83 Mbps.Ayudas para contratos predoctorales de Formación del Profesorado Universitario FPU (Convocatoria 2015), Grant/Award Number: FPU15/06837; Programa Estatal de Investigación Científica y Técnica de Excelencia (Convocatoria 2017), Grant/Award Number: TIN2017-84802-C2-1-P; Programa Estatal De Investigación, Desarrollo e Innovación Orientada a los retos de la sociedad (Convocatoria 2016), Grant/Award Number: TEC2016-76795-C6-4-R; ERANETMED, Grant/Award Number: ERANETMED3-227 SMARTWATIRRego Mañez, A.; Sendra, S.; García-García, L.; Lloret, J. (2019). Adapting reinforcement learning for multimedia transmission on SDN. Transactions on Emerging Telecommunications Technologies. 30(9):1-15. https://doi.org/10.1002/ett.3643S11530

Multicast-based Weight Inference in General Network Topologies

Network topology plays an important role in many network operations. However, it is very difficult to obtain the topology of public networks due to the lack of internal cooperation. Network tomography provides a powerful solution that can infer the network routing topology from end-to-end measurements. Existing solutions all assume that routes from a single source form a tree. However, with the rapid deployment of Software Defined Networking (SDN) and Network Function Virtualization (NFV), the routing paths in modern networks are becoming more complex. To address this problem, we propose a novel inference problem, called the weight inference problem, which infers the finest-granularity information from end-to-end measurements on general routing paths in general topologies. Our measurements are based on emulated multicast probes with a controllable “width”. We show that the problem has a unique solution when the multicast width is unconstrained; otherwise, we show that the problem can be treated as a sparse approximation problem, which allows us to apply variations of the pursuit algorithms. Simulations based on real network topologies show that our solution significantly outperforms a state-of-theart network tomography algorithm, and increasing the width of multicast substantially improves the inference accuracy

Decentralized Control of Distributed Cloud Networks with Generalized Network Flows

Emerging distributed cloud architectures, e.g., fog and mobile edge computing, are playing an increasingly important role in the efficient delivery of real-time stream-processing applications such as augmented reality, multiplayer gaming, and industrial automation. While such applications require processed streams to be shared and simultaneously consumed by multiple users/devices, existing technologies lack efficient mechanisms to deal with their inherent multicast nature, leading to unnecessary traffic redundancy and network congestion. In this paper, we establish a unified framework for distributed cloud network control with generalized (mixed-cast) traffic flows that allows optimizing the distributed execution of the required packet processing, forwarding, and replication operations. We first characterize the enlarged multicast network stability region under the new control framework (with respect to its unicast counterpart). We then design a novel queuing system that allows scheduling data packets according to their current destination sets, and leverage Lyapunov drift-plus-penalty theory to develop the first fully decentralized, throughput- and cost-optimal algorithm for multicast cloud network flow control. Numerical experiments validate analytical results and demonstrate the performance gain of the proposed design over existing cloud network control techniques

P4-based efficient packet retransmission using in-network cache ― Introduction to Coded-MPMC one-to-many transfer ―

データセンタ内や地理的に分散配置されたデータセンタ間で, 大容量のファイルやソフトウェアの共有, 複製, または移動によるトラヒック量の急激な増加に対応するために, 高速かつ高効率な一対多ファイル転送の重要性が高まっている. そこで私たちは, 全二重ネットワーク上で各受信者が送信者からの最大フロー量を完全に利用して, 理論最小時間でファイル取得を完了するために, Coded-MPMC(送信者符号化を導入した複数経路マルチキャスト)による一対多転送を提案した. Coded-MPMC転送はOpenFlowプロトコルを用いて実装されており, 各受信者が理論最小時間に近い時間でファイル取得を行えることが確認されている. しかしパケットロスが発生した場合, 送信者と受信者間で行われる再送処理に時間がかかってしまうことで取得完了時間が遅くなり, Coded-MPMC転送全体のパフォーマンスが悪化してしまうという問題がある. そこでデータプレーンをプログラム可能なP4言語を利用し, スイッチ自身がキャッシュしたデータを用いて再送応答を行う再送処理法を実装した. 本報告では, Coded-MPMC転送にこの開発したスイッチを導入することで, 再送処理に要する時間の短縮や再送に利用されるネットワーク資源の節約を行えることを示す. / Fast and efficient one-to-many file transfers are increasingly essential to deal with the rapid increase in traffic due to the sharing, replication, or movement of large-sized files and software within the data center and between geographically distributed data centers. Therefore, we proposed a one-to-many transfer using Coded-MPMC (Multipath Multicast with Sender coding) to complete the file retrieval in the theoretical minimum time by fully utilizing the max-flow value from the sender to each recipient over a fully-controlled network with full-duplex links. The Coded-MPMC transfer is implemented using the OpenFlow protocol, and we confirmed that each recipient could retrieve the file in the time close to its theoretical lower-bound time. However, when packet loss occurs, the retransmission process between the sender and the recipient slows down the retrieval completion time, and the performance of the Coded-MPMC transfer deteriorates. To solve this problem, using the P4 language which can program the data plane, we implemented the efficient retransmission method that the switch itself responds to retransmission requests using cached data instead of the sender. In this paper, we introduce the developed switch to the Coded-MPMC transfer, and show that the new retransmission allows to shorten the retrieval completion time of each recipient and save the network resources used for the retransmission when packet loss occurs.電子情報通信学会 情報ネットワーク研究会（IN）, 2021年3月4日-5日, オンライン開

Software Defined Networks based Smart Grid Communication: A Comprehensive Survey

The current power grid is no longer a feasible solution due to ever-increasing user demand of electricity, old infrastructure, and reliability issues and thus require transformation to a better grid a.k.a., smart grid (SG). The key features that distinguish SG from the conventional electrical power grid are its capability to perform two-way communication, demand side management, and real time pricing. Despite all these advantages that SG will bring, there are certain issues which are specific to SG communication system. For instance, network management of current SG systems is complex, time consuming, and done manually. Moreover, SG communication (SGC) system is built on different vendor specific devices and protocols. Therefore, the current SG systems are not protocol independent, thus leading to interoperability issue. Software defined network (SDN) has been proposed to monitor and manage the communication networks globally. This article serves as a comprehensive survey on SDN-based SGC. In this article, we first discuss taxonomy of advantages of SDNbased SGC.We then discuss SDN-based SGC architectures, along with case studies. Our article provides an in-depth discussion on routing schemes for SDN-based SGC. We also provide detailed survey of security and privacy schemes applied to SDN-based SGC. We furthermore present challenges, open issues, and future research directions related to SDN-based SGC.Comment: Accepte

Coded-MPMC: One-to-Many Transfer Using Multipath Multicast With Sender Coding

One-to-many transfers in a fast and efficient manner are essential to meet the growing need for duplicating, migrating, or sharing bulk data among servers in a datacenter and across geographically distributed datacenters. Some existing works utilize multiple multicast trees for a one-to-many transfer request to increase network link utilization and its transfer throughput. However, since those schemes do not fully utilize the max-flow value of transmission from a single sender to each recipient, there is room for each recipient to retrieve data more quickly. Therefore, assuming fully-controlled networks with full-duplex links, we pose a problem to find a set of multicast flows with an allocation of block-wise transmissions by which each of multiple recipients with diverse max-flow values from the sender can utilize its own max-flow value. Based on that, assuming a sender-side coding capability on file blocks, we design a schedule of block transmissions over multiple phases by which each recipient can achieve a lower-bound of its file retrieval completion time, i.e., the file size divided by its own max-flow value. This paper presents the coded Multipath Multicast (Coded-MPMC) for one-to-many transfers with heuristic procedures to find a desired set of multicast flows on which block transmissions are scheduled. Through extensive simulations on large-scale real-world network topologies and different types of randomly-generated synthetic topologies, the proposed method is shown to design a desired schedule efficiently. A preliminary implementation on OpenFlow is also reported to show the fundamental feasibility of Coded-MPMC

Software defined networking for radio telescopes: a case study on the applicability of SDN for MeerKAT

Scientific instruments like radio telescopes depend on high-performance networks for internal data exchange. The high bandwidth data exchange between the components of a radio telescope makes use of multicast networking. Complex multicast networks are hard to maintain and grow, and specific installations require modified network switches. This study evaluates Software Defined Networking (SDN) for use in the MeerKAT radio telescope to alleviate the management complexity and allow for a vendor-neutral implementation. The purpose of this dissertation is to verify that an SDN multicast network can produce suitable paths for data flow through the network and to see if such an implementation is easier to maintain and grow. There is little literature regarding SDN for radio telescope networks; however, there is considerable work where different aspects of SDN are discussed and demonstrated for video streaming. SDN with multicast for video streaming, although simpler, forms the background research. Considerable work was put into understanding and documenting the different aspects of a radio telescope affecting the data network. The telescope network controller generates the OpenFlow rules required by the SDN controller and is a new concept introduced in this work. The telescope network controller is fitted with two placement algorithms to demonstrate its flexibility. Both algorithms are suitable for the expected workload, but they produce very different traffic patterns. The two algorithms are not compared to one another, they were created to demonstrate the ease of adding domain specific knowledge to an SDN. The telescope network controller makes it easy to introduce and use new flow placement algorithms, thus making traffic engineering feasible for the radio telescope. Complex multicast networks are easier to maintain and grow with SDN. SDN allows customised packet forwarding rules typically unattainable with standard routing and other standard network protocols and implementations. A radio telescope with a software-defined data network is resilient, easier to maintain, vendor-neutral, and possesses advanced traffic engineering mechanisms

Auto-bandwidth control in dynamically reconfigured hybrid-SDN MPLS networks

The proposition of this work is based on the steady evolution of bandwidth demanding technology, which currently and more so in future, requires operators to use expensive infrastructure capability smartly to maximise its use in a very competitive environment. In this thesis, a traffic engineering control loop is proposed that dynamically adjusts the bandwidth and route of flows of Multi-Protocol Label Switching (MPLS) tunnels in response to changes in traffic demand. Available bandwidth is shifted to where the demand is, and where the demand requirement has dropped, unused allocated bandwidth is returned to the network. An MPLS network enhanced with Software-defined Networking (SDN) features is implemented. The technology known as hybrid SDN combines the programmability features of SDN with the robust MPLS label switched path features along with traffic engineering enhancements introduced by routing protocols such as Border Gateway Patrol-Traffic Engineering (BGP-TE) and Open Shortest Path First-Traffic Engineering (OSPF-TE). The implemented mixed-integer linear programming formulation using the minimisation of maximum link utilisation and minimum link cost objective functions, combined with the programmability of the hybrid SDN network allows for source to destination demand fluctuations. A key driver to this research is the programmability of the MPLS network, enhanced by the contributions that the SDN controller technology introduced. The centralised view of the network provides the network state information needed to drive the mathematical modelling of the network. The path computation element further enables control of the label switched path's bandwidths, which is adjusted based on current demand and optimisation method used. The hose model is used to specify a range of traffic conditions. The most important benefit of the hose model is the flexibility that is allowed in how the traffic matrix can change if the aggregate traffic demand does not exceed the hose maximum bandwidth specification. To this end, reserved hose bandwidth can now be released to the core network to service demands from other sites